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Biomedical subjects

A Ostry

Publications and source records attributed to A Ostry.

At least 19 recordsLinked to original sources
PubMed2001

Invasion of murine respiratory epithelial cells in vivo by Burkholderia cepacia.

Pulmonary infections caused by Burkholderia cepacia are an important cause of morbidity and mortality in cystic fibrosis (CF) patients. Several features suggestive of invasion and intracellular sequestration of B. cepacia in CF are persistence of infection in the face of antibiotic therapy and a propensity to cause bacteraemic infections in patients with CF. A mouse respiratory challenge model was used to investigate the invasion phenotype of B. cepacia in vivo. After intratracheal inoculation, epidemic B. cepacia strains translocated from lung to liver and spleen; however, all bacteria were cleared from all organs within 7 days. B. cepacia strains, irrespective of cable piliation, were capable of attaching to and then invading murine respiratory tract epithelial cells. Histopathological examination of lungs showed interstitial infiltrates comprised mainly of polymorphonuclear leucocytes and were associated with widened alveolar septa. Electron microscopy demonstrated B. cepacia within epithelial cells and pulmonary macrophages. This study provides support for in-vitro observations that B. cepacia strains from patients with CF adhere to and then invade respiratory epithelial cells. The invasion phenotype in B. cepacia may be an important virulence factor in CF infections.

Animals↗
PubMed2000

Life-threatening gastrointestinal hemorrhage due to juvenile polyposis.

A 14-yr-old, previously healthy boy presented with massive lower GI hemorrhage. After the routine endoscopic and radiological evaluation, laparotomy and intraoperative colonoscopy revealed multiple polyps in the colon. A hemicolectomy was performed because of the severity of hemorrhage. A diagnosis of juvenile polyposis was made based upon histological findings and the family history. This is an extremely unusual presentation of juvenile polyposis and has been reported only once before. The clinical features, diagnosis, and therapeutic options for juvenile polyposis are discussed. Juvenile polyposis, although a rare condition in the pediatric population, should be considered in the differential diagnosis of life-threatening GI hemorrhage.

Adenomatous Polyposis Coli↗
PubMed2000

Childhood cancer in the offspring of male sawmill workers occupationally exposed to chlorophenate fungicides.

The objective of this study was to determine whether paternal occupational exposure to chlorophenol fungicides and their dioxin contaminants is associated with childhood cancer in the offspring of sawmill workers. We used data from 23,829 British Columbian sawmill workers employed for at least 1 continuous year between 1950 and 1985 in 11 sawmills that used chlorophenates. Probabilistic linkage of the sawmill worker cohort to the provincial marriage and birth files produced an offspring cohort of 19,674 children born at least 1 year after the initiation of employment in the period 1952-1988. We then linked the offspring cohort to the British Columbia Cancer Registry. We included all malignancies in cases younger than 20 years of age that appeared on the cancer registry between 1969 and 1993. We calculated standardized incidence ratios (SIRs) using the British Columbia population as a reference. A nested case-control analysis assessed the effects of paternal cumulative exposure and windows of exposure on the risk of developing cancer in the offspring. We identified 40 cases of cancer during 259,919 person-years of follow-up. The all-cancer SIR was 1.0 [95% confidence interval (CI), 0.7-1.4]; the SIR for leukemia was 1.0 (CI, 0.5-1.8); and the SIR for brain cancer was 1.3 (CI, 0.6-2.5). The nested case-control analysis showed slightly increased risks in the highest categories of chlorophenol exposure, although none was statistically significant. Our analyses provide little evidence to support a relationship between the risk of childhood cancer and paternal occupational exposure to chlorophenate fungicides in British Columbian sawmills.

Adolescent↗
PubMed2000

Downsizing and industrial restructuring in related to changes in psychosocial conditions of work in British Columbia sawmills.

OBJECTIVES: This paper investigates changes in the psychosocial and physical work conditions of the sawmill industry in British Columbia, Canada, over the past 35 years. METHODS: Shifts in work conditions were examined within the context of historical changes in sawmill labor demography and job taxonomy as the industry was both downsized and restructured, largely in response to an economic recession in the early 1980s. RESULTS AND CONCLUSIONS: Downsizing eliminated approximately 60% of the work force and 1/4 of sawmill job titles. Although all the job categories in restructured sawmills showed increased levels of control, the gradient in control across job categories was steeper in 1997 than in 1965; this change may have important health implications particularly for the unskilled workers in the restructured mills.

British Columbia↗
PubMed1998

Gender, work roles and psychosocial work characteristics as determinants of health.

This paper aims to identify gender similarities and differences in psychosocial work characteristics for those in and out of paid employment, to inform research on possible health-related effects. Specifically five questions are addressed: do women report poorer work characteristics than men; are gender differences related to specific characteristics; do work characteristics differ between full- and part-time women workers and between those in paid and unpaid work; are socio-economic gradients in work characteristics similar for men and women; and, if there are gradients, do they differ between women in paid and unpaid work? Analyses are based on the 33 year follow-up of the 1958 British birth cohort. Four psychosocial work characteristics were examined: learning opportunities, monotony, pace of work, and flexibility of breaks. Women reported more negative work characteristics than men, primarily because of differences in learning opportunities (26% lacked opportunity compared with 13% of men) and monotonous work (47 and 31% respectively). Women in full-time employment reported fewer negative characteristics (27%) than part-time (39%) or home-workers (36%). Home-workers had fewer opportunities for learning (36%) and greater monotony (49%) than paid workers (21 and 22% respectively), however fewer home-workers reported inability to control the work pace (11% compared to 23%) and inflexibility of breaks (21% compared to 47%). Socio-economic gradients in work characteristics were similar among men and women, except for flexibility of break times. A socio-economic gradient in work characteristics was found for full- and part-time workers, but not among home-workers. Differences in self reported health were also examined: a social gradient was found for all employment status groups, being strongest for home-workers despite the absence of a gradient in negative work characteristics. In conclusion, these marked gender differences in psychosocial work characteristics need to be considered in future research on work and health.

Adult↗
PubMed1998

Fertility among a cohort of male sawmill workers exposed to chlorophenate fungicides.

The purpose of this study was to determine whether exposure to chlorophenate fungicides and their dioxin contaminants is associated with male infertility among sawmill workers. The study was conducted using fertility data compiled from 26,487 sawmill workers in 14 British Columbian sawmills. Our analysis was restricted to workers who had been employed for at least 1 continuous year between 1950 and 1985 and to live-births born at least 1 year after the initiation of employment in the period 1955-1988. We assessed fertility trends by internal comparison using Mantel-Haenszel rate ratios and by calculating standardized fertility ratios using an external and an internal reference population. We identified 19,684 births in the study period. Initially, both external and internal analyses showed that sawmill workers from mills using chlorophenates had lower fertility than workers employed in mills not using chlorophenates. After controlling for time since first hire, however, we found no inverse relation between cumulative exposure to chlorophenate fungicides and fertility. Based on the results of our study, there is little evidence for a reduction in fertility among chlorophenate-exposed sawmill workers in British Columbia. The analyses indicate the importance of time since hire as a potentially strong confounder in this type of investigation.

Adult↗
PubMed1997

Mortality and cancer incidence among sawmill workers exposed to chlorophenate wood preservatives.

OBJECTIVES: This study examined the association between exposure to chlorophenates and the risk of soft tissue sarcoma; non-Hodgkin's lymphoma; Hodgkin's disease; and cancers of the lung, nose, and nasopharynx. METHODS: A retrospective cohort study was conducted of 26487 workers employed for at least 1 year between 1950 and 1985 in 11 chlorophenate-using and 3 non-using sawmills in British Columbia, Canada. Exposures by job were ascertained with interviews of senior employees. RESULTS: Probabilistic record linkage to the Canadian Mortality Data Base and the British Columbia Cancer Registry found 4710 deaths between 1950 and 1990, and 1547 incident cases of cancer between 1969 and 1989. None of the cancers of interest had elevated mortality related to chlorophenate exposure. Non-Hodgkin's lymphoma incidence (n = 65) increased with increasing chlorophenate exposure hours, yielding the following standardized incidence ratios: less than 120 hours 0.68; 120 to 1999 hours, 0.59; 2000 to 3999 hours, 1.04; 4000 to 9999 hours, 1.02; and 10000 or more hours, 1.30. CONCLUSIONS: These results are consistent with the borderline positive associations seen in other recently reported studies of chlorophenate-exposed workforces.

British Columbia↗
PubMed1996

Reliability of retrospective chlorophenol exposure estimates over five decades.

For a cohort study of chlorophenate-exposed sawmill workers, historical exposures from the 1940s to the 1980s were estimated by teams of 9-20 employees (each interviewed individually). The mill histories were divided into eras when jobs and exposures were relatively stable. Raters with at least 5 years of work experience in an era were asked to estimate the frequency and duration of exposure for each job in the mill. Reliability measures for these estimates were calculated for each of the 39 mill and time period combinations, using the individual intraclass correlation coefficient (ICCind) to assess agreement between raters and the group intraclass correlation coefficient (ICCgroup) to assess the stability of the mean estimates of exposure. ICCind were low, with means that increased from 0.24 to 0.35 over the five decades. ICCgroup were considerably higher (means increasing from 0.78 to 0.88 over time), indicating that the number of raters used in this study was sufficient to produce stable average estimates of exposure throughout the study period. These data confirm the intuitive expectation that reliability of exposure estimates decreases when reconstruction of conditions in the distant past is required, and therefore that the random component of exposure misclassification is a greater threat to validity in these earlier time periods.

Analysis of Variance↗
PubMed1996

Reproductive effects of paternal exposure to chlorophenate wood preservatives in the sawmill industry.

OBJECTIVES: The purpose of the study was to determine whether paternal occupational exposure to dioxincontaminated chlorophenols is associated with an increased risk of congenital anomalies or other adverse reproductive outcomes in offspring. METHODS: As a result of a multistep linkage, 19675 births between 1952 and 1988 were identified as children of a cohort of 9512 fathers who had worked at least one year in British Columbia sawmills where chlorophenate wood preservatives had been used. A nested case-referent analysis was applied, using conditional logistic regression, with five referents matched per case according to year of birth and gender. Chlorophenate exposure was based on expert raters' estimations of hours of exposure applied to specific time windows prior to birth. RESULTS: The offspring of male sawmill workers were at increased risk for developing congenital anomalies of the eye, particularly congenital cataracts; elevated risks for developing anencephaly or spina bifida and congenital anomalies of genital organs were shown according to specific windows of exposure. No associations were found for low birthweight, prematurity, stillbirths, or neonatal deaths. CONCLUSIONS: The study adds further support to the hypothesis of male-mediated developmental toxicity. Paternal exposure to chlorophenates was associated with the development of certain congenital anomalies in offspring.

Abnormalities, Drug-Induced↗
PubMed1992

Recognizing acute health effects of substitute fungicides: are first-aid reports effective?

Recently, many British Columbia sawmills stopped using traditional chlorophenate anti-sapstain fungicides and substituted 2-(thiocyanomethylthio) benzothiazole (TCMTB) and copper-8-quinolinolate (Copper 8). We conducted a cross-sectional study with two aims: to ascertain which acute health effects, if any, were associated with the use of the substitute fungicides; and to determine the effectiveness of first-aid records as a means of detecting acute health outcomes. Workers in five coastal sawmills were asked to complete a self-administered questionnaire about symptoms considered potentially related and unrelated to fungicide exposure, and about injuries commonly reported in sawmills. In addition, we collected first-aid records from the mills, and asked senior workers to estimate the duration of exposure to fungicides for each job. Symptoms found to be consistently elevated in TCMTB mills included dry skin around the eyes, blood-stained mucus from the nose, nose bleed, peeling skin, burning or itching skin, and skin redness or rash. No symptoms were consistently elevated in the Copper 8 mills. Symptoms related to TCMTB exposure were recorded only 12 times in first-aid logs during the study period (versus 335 questionnaire self-reports). This low symptom-recording frequency may be a function of established patterns of first-aid use in which illness symptoms are reported less frequently than injuries.

Acute Disease↗
PubMed1989

A comparison of exposure estimates by worker raters and industrial hygienists.

The validity and reliability of nine senior sawmill workers' estimates of frequency, duration, and routes of exposure were compared with individual workers' ratings of their own job titles and industrial hygienists' ratings of all job titles in the plant. The reliability of the senior workers' mean exposure estimates [group intraclass correlation coefficient (ICC) = 0.71] compared favorably with those of three pairs of hygienists (group ICC = 0.57, 0.67, and 0.81). The validity of their ratings was assessed in a comparison with urinary chlorophenate measurements representing 92% of the job titles in the sawmill. The senior workers' ratings [coefficient of determination (R2) = 0.22] resembled those of two pairs of industrial hygienists (R2 = 0.24, 0.22) and was significantly greater than that of the third pair (R2 = 0.08). The validity of the self-reports was also low (R2 = 0.15), but the difference was not statistically significant. Senior workers' exposure ratings appear to be as effective as the other methods tested.

Air Pollutants, Occupational↗
PubMed1988

Validity and reliability of a method for retrospective evaluation of chlorophenate exposure in the lumber industry.

This paper describes the validity and reliability of a method to retrospectively assess exposure to antisapstain agents used in sawmills (chlorophenates). The method is based on experienced workers' estimates of exposure for each job title at the sawmill where they work. At a pilot mill, 10 randomly selected workers estimated the frequency and duration of exposures to chlorophenates for all 59 job titles. The reliability of their mean exposure estimates was very high, with an intraclass correlation coefficient for all raters of 0.91 (based on a calculated index of exposure). To assess validity, urinary chlorophenate levels were measured for 86% of the workers at the mill during the summer and/or fall, and compared to experienced workers' estimates of exposure. The correlation between workers' exposure estimates and the urinary chlorophenate levels for each job title were consistently above 0.65 for all analyses and greater than 0.72 when summer and fall urine sample results were averaged. The evidence indicates that the validity and reliability of worker exposure estimates are high enough to justify investigation of the method's generalizability to other sawmills.

Chlorophenols↗
PubMed1984

Pharmacokinetics and metabolism of 5-fluorouracil following subconjunctival versus intravenous administration.

Two groups of six rabbits each were given 6.25 mg/kg of 6-carbon-14-labelled 5-fluorouracil (5-FU) either subconjunctivally or intravenously. The levels of the drug in the serum, the urine and the ocular humours 0.5, 1, 2, 4, 8 and 12 hours later were measured by high-pressure liquid chromatography, which distinguished between 5-FU and its metabolites. The peak levels of the parent drug in the serum and the urine were similar with the two routes of administration; however, compared with intravenous injection, subconjunctival injection resulted in 125 and 380 times the peak concentration of 5-FU in the anterior chamber aqueous and the vitreous respectively.

Animals↗
PubMed1980

Concentrations of tritiated methotrexate in ocular compartments, serum and urine after subconjunctival and intravenous injection.

Forty-eight rabbits were given 6.25 mg/kg of tritiated methotrexate subconjunctivally or intravenously. Concentrations of the drug in ocular compartments, the serum and the urine were measured 0.5, 1, 2, 4, 8, 12, 24 and 48 hours after injection. Compared with intravenous administration subconjunctival injection resulted in 4.5 times more methotrexate in the anterior chamber, but the concentrations in the vitreous were the same with the two routes of administration. The serum levels of methotrexate, however, were nine times lower after subconjunctival injection.

Animals↗
PubMed1979

Intraocular penetration of subconjunctivally administered 14C-fluorouracil in rabbits.

Fluorouracil is given for a variety of neoplasms by various administrative routes. Toxicity of susceptible normal tissue limits systemic dosage, but at this level intraocular tissue may not receive tumor-inhibiting concentrations. Subconjunctival administration of 6.25 mg of 14C-fluorouracil in 0.5-mL dosages resulted in a peak anterior chamber concentration of 69.5 micrograms/mL and a peak vitreous concentration of 10.5 micrograms/mL over the 12 hours tested. This resulted in no visible ocular damage. The intraocular levels achieved were greater than the concentration reported to inhibit selected tumors. The total dosage administered was considerably below the level of systemic toxicity.

Animals↗
PubMedDate not supplied

The history of injury and industrial disease rates in British Columbia from 1950 to 1996.

The purpose of this investigation is to describe changes in industrial injury and disease rates in British Columbia between 1950 and 1996. Data on injury and disease rates were abstracted manually from WCB Annual Reports for the years 1950 through 1996. A number of interesting patterns emerge. Death report rates declined by 79% during the study period. Injury report rates also declined, although less dramatically, by 29%, over the 46-year study period with much of the decrease occurring prior to 1970. Accepted claims for impact injuries declined prior to the 1970s. At the same time claims for strain injuries began to increase with the pace of increase accelerating after 1970. A similar pattern was observed for industrial disease as the incidence of strain-based disease claims also increased rapidly after 1970. This pronounced trend towards "strain-related" injuries and disease creates new challenges for adjudication and prevention. The identification of work organizational and job structural features which contribute to strain injury and disease and the elucidation of the relationship between these conditions and "physical" strain injuries should be a priority for injury epidemiologists and WCB.

Accidents, Occupational↗